Gold thioglucose competitively inhibits deiodination of both T4 and rT3 catalyzed by a transiently tranfected 5' DI enzyme. The purpose of this study is to investigate whether gold compounds used as treatment for rheumatoid arthritis cause alterations of thyroid hormone metabolism. Whether gold affects thyroid function in patients with either chemical thyroid disease or overt hypothyroidism will also be investigated. Uses only the CORE lab.